Children with Attention-Deficit/Hyperactivity Disorder (ADHD) participated in double-blind placebo-controlled randomized trails of stimulants while undergoing anatomic imaging with magnetic resonance imaging (MRI). The four approached are (1) anatomic imaging with magnetic resonance imaging, (2) neuropharmacology, (3) genetic studies, and (4) neurophysiological investigations. In anatomic studies, girls with ADHD have shown similar basal ganglia and prefrontal brain abnormalities to those seen in our previous study of boys. Subjects also participate in a longitudinal study of brain development. An on-going follow-up study compares a brain maturation of subjects with good and poor ? one year?s outcome. These subjects and others also participate in studies of the genetics of ADHD using family association and affected-sibling designs in collaboration with a multi-center multi-institute consortium. Associated studies document relationship with NET1, DRD4 and DRD1 and diagnosis of ADHD (1). Long term follow-up shows plastic brain changes in relation to good outcome (5). DRD4 risk gene is related to cortical thinning in childhood and good outcome during adolescence. A replication with remitted and nonremitted adult subjects is planned.